Am I not physically fast enough for my job?

Not physically fit enough for my job.

So I took a job working with kids with behavioral issues because it was entry level and the pay was good.

It's common for us to be attacked by our clients and they teach us how to get out of being attacked and how to escape.

My only problem now is that I don't know if I'm physically fit enough for the job.

If one of my clients runs after me with the intent to hurt me I need to try and outrun them and I can't run fast enough.

And there are times where I have to think of my safety but prioritize the client safety.

My only issue is that I don't know if I can run fast enough from a client while looking back to see if they're still chasing me.

I have a team and we stay in communication using a cell phone My only issue is I can't think of how to run from the client, while looking back to see if they're still running towards me or running somewhere else or they could get hurt, while texting I need help.

If I can't run fast enough what am I supposed to do? Do I quit or wait to be fired? I'm also worried that if I'm running and a kid ends up running to the street and getting killed I get charged for it.

When I asked for advice on how to outrun some of our clients My boss just says "I need to go to the gym and work on running faster.

I might already be fit enough I'm not 100% sure. Because if a kid grabs me I have an idea what moves to do to save myself. But I can't outrun them. Does anyone have any advice?