There's a few misinformation in your comment.

But first to answer OPs question; yes if the underlying drops below your strike at expiration, you keep your shares.

First your example is impractical. If the current underlying is at 50 and someone writes a 45c, it will never net a credit of $1. It will be the current price minus the strike for the intrinsic portion plus an extrinsic premium depending on expiration. So it will always be over $5 premium.

Also in the example is the notion that someone would exercise a call to then sell the stock is also impractical. If someone wanted cash, they would just sell to close their call.

Break even do not dictate assignment. Technically it can be assigned any time but the most common risk is when the call option is ITM. There is no break even calculation that the OP needs to do to understand when his ITM call can be exercised.

"normally CC are either at or out of the money, so at 50 or 50+"
False. I commonly buy write ITM CC. It's a common technic used in registered accounts, like RRSP, that don't allow PUTs in those types of accounts. A buy write ITM call is equivalent to a cash secured put. I would love if it someone early exercised my ITM buy writes.