"But that's the weapon arm. I need to control it."
I shake my head. "Watch me." I pass/parry/enter "What can you reach with your knife?" I know the answer- if my hand weren't under his arm he might be able to get my thigh, but it is. If he was extremely flexible he just might be able to nick my ear or ruffle my hair. Maybe. Just because it is scary, doesn't mean it can hurt you. What I say is, "If you can't reach me with it, I don't need to waste resources on it. It is controlled, but by position, not grip."
There's a lot of that kind of stuff out there- solutions to problems that aren't problems. We talked about it later. Someone grabs your wrists, what do you do? I just say, "I know you're desperate but I am not going out with you." I know where his hands are. Where his feet are. What he can do and what he can't. For most things he needs to let go, for the one he doesn't, the head butt, I'll feel his intention. There is no problem here, unless you psych yourself into one.
Same with grabbing the shirt. It's an aggressive, scary move if you buy into the hype. Put it down on paper and suddenly it's a gift. "Hi, my name's Ray and I'll be your attacker today. I've decided to open by tying up both my hands in a way that can't really hurt you, leaving your hands free and my knees, throat, ears and lots of other good stuff in easy reach."
Lots of the groundfighting positions on the bottom are good places to rest. There are some holds- kesa gatame and kami shiho gatame to name two, where the person can't hurt you without changing the hold. The only danger in either is to struggle yourself to exhaustion. There is no problem here, not until the bad guy's friends show up.
Recognizing a problem is a critical strategic skill. Recognizing when something is not a problem and you can save your resources is a critical tactical skill.