I was Pes C2 at that time due to the dislocated shoulder.
This was my BMT recourse, therefore it was conducted by a Guards unit and not a normal BMT school, but most of the "recruits" were Pes B or worse.
Letter of excuse? I had something even better - I dislocated my shoulder during my first BMT just doing warm ups.
I walked up to my PTI with shoulder dislocated (and loads of pain), told him my shoulder dislocated and need to go see MO. He didn't believe me, of course. Probably never seen a dislocated shoulder before.
I walked, accompanied by a sergent all the way to the MO, had him confirm my dislocation then he and a medic had to force it back into the socket because it had been out of the socket for so long. (at least an hour)
3 weeks after that I was downgraded to Pes C2.
Usually arm injury is only given C1, so you can see how bad it was to be C2 perm.
And you know the funny thing? All that time I could have easily put the shoulder back in the socket (just suffer pain and soreness for a few days), but I had to do the whole charade just to "prove" I had a shoulder dislocation problem.
haha, and I still remember my MO was CPT Vincent Cheong, the most siao on MO in the whole Nee Soon Camp. He had a reputation of NOT giving MC.