Edited...
However, in a situation where the investors is expecting his weekly income in two days time and he sees a drastic dip, he can take out only the amount of money that he has planned to DCA with on that week from his discretionary income and buy bitcoin so that, he would not miss the dip. When he gets paid in two days time, he can replace the money which he took from his discretionary income.
I get your POV clearly, but I'll like you to note something as well, every bad behavior isn't a product of one time activity, it's a belief that is cultivated and accepted as normal from the mind and is played out constantly. When the investor tampers with his emergency fund to catch up with a dip, it termed normal but it's a bad discipline, he repeats it again and is termed smart, overtime it may feel normal for him to tamper with his emergency fund as long as he feels his income is on the way and there's no guarantee that he continues to replace what he's removed and unintentionally, he continues spending his emergency fund until it's very low only to be caught in reality check when there's a real emergency and nothing much left to Carter for it and then his portfolio is tempered.
If there's any strictness left in you, apply it to your emergency fund and remain disciplined that it's not used for anything else apart from a real emergency.