Both of which are "right this second" situations. Unless you strap your knife to the shaft and LEAVE it there, the whole mental exercise is a wonderful fantasy. You are better off having a long(ish) stick with a metal cap or a slightly pointy trail tip in your hand, and your knife on your belt.

One of the funny things about spears- people think it goes in, and then.... the animal stops? Spears with BIG cross bars, like a European boar spear, are the only kind that I have any faith in when dealing with something that is just as likely to charge up the shaft and gut me if it can.

A flat tip, used like a tsubo (a bo staff with metal shod tips), is much less likely to cause you to have this worry. You can thrust with it, and if you have the speed (not just brute strength) it will break bones. Broken bones stop things a lot faster than poking a hole in it.

I maintain a good oak or maple staff with a shod base, wrapped with paracord that has a lanyard loop (fast reversals), and with a fishspear head in your pack IF you need to use it, is much, much better than sticking your one and only knife on the end of the long pokey stick.

The other reason is, if something gets inside my staff, I WANT my blade in my hand. If it comes to tooth and claw, I want to have my claw where it belongs, in my paw.