AITA for getting frustrated and stepping in when another intern avoids doing proper root cause analysis?

Note: Would appreciate advice on how to handle this without damaging my own reputation.

I’m an intern at a successful startup. I joined last winter and was onboarded alongside another intern (let’s call him Rahul). We were in the same team, had the same HR sessions, and helped each other settle in. Normal intern stuff. Our roles were different though: I’m an AI engineer, and he’s a Python developer, so we didn’t collaborate much initially.

About three months in, I accidentally overheard a meeting between my reporting manager and some senior engineers where my manager straight up said about Rahul: “Rahul chutiya hai.” (Rahul is a c\*nt)

Other seniors defended him with the usual: “sab intern chutiye hote hai, hum bhi intern the.”

I wasn’t meant to hear this, but I work closely with a senior engineer (let’s call him Brian, \~3 YoE, very skilled and important across teams), so I was nearby. Brian had worked with Rahul for those three months and was clearly frustrated. Rahul, on the other hand, used to complain that Brian scolds a lot.

Here’s the thing: Brian scolds me more than Rahul. I take it positively because I know I mess up sometimes and I learn from it. With Rahul, Brian was actually more gentle.

Rahul’s feedback from Brian (which I later learned):

1. Rahul gets defensive when his faults are pointed out
2. Rahul avoids proper RCA and prefers workarounds
3. Rahul is extremely poor at communication

Fast forward to now. I’ve been working directly with Rahul for the last 3 days, and I’m already frustrated.

In a casual conversation, my reporting manager asked for updates and said, “yaar Rahul ka nahi hoga.” (I think he meant that Rahul won’t be converted to fulltime) (what he said literally tranlates as “rahul won’t make it”)

(Not realising that my manager was talking about fulltime conversion) I said, “I’m frustrated too.”

The problem is that Rahul just does NOT get things. Every time I get frustrated, I feel like an asshole because I end up saying things like “I did his part of the work,” which sounds arrogant, but is literally what’s happening.

Concrete example:

On Jan 14, an engineer raised an issue in my project. Rahul suggested a workaround. It failed. I asked him to do a proper RCA. His response was:

“mere side toh reproduce nahi hua.”

(It didn’t reproduce on my end)

I’ve repeated multiple times:

I don’t care if it didn’t reproduce for you. I want to know why it happened.

He doesn’t seem to understand the difference between:

\- fixing symptoms vs understanding root cause

\- “works on my machine” vs actually investigating

Now I’m stuck between:

\- Being patient and mentoring him (even though we’re both interns)

\- Letting my frustration show and looking like a toxic asshole

Has anyone dealt with this situation as an intern working with another intern who just doesn’t get basic engineering fundamentals? How do you handle this without sabotaging your image or mental peace?

TL;DR:

I’m an intern working with another intern who avoids RCA, gets defensive, and defaults to workarounds like “works on my machine.” Seniors and my manager have privately expressed frustration using unprofessional language. Now that I’m working directly with him, I’m getting frustrated too and sometimes end up doing his work. Looking for advice on how to handle this professionally without becoming toxic or damaging my reputation.