could be, that the "camp" mentioned just refers to the camp of their immediate family, ?
The "Insight" book disagrees:
https://wol.jw.org/en/wol/d/r1/lp-e/1200000872
The size of this camp of Israel was very great. The above register figures total 603,550 fighting men, in addition to women and children, old folks and handicapped, 22,000 Levites, and “a vast mixed company” of aliens—perhaps all together 3,000,000 or more. (Ex 12:38, 44; Nu 3:21-34, 39) How much area such an encampment would cover is not certain; estimates vary greatly.
Gotta love how they sidestep the size issue - "estimates vary greatly". Yeah, not sure whether it would thousands or merely hundreds of square miles. In any event, the official WT position is that "the camp" is the whole thing, so "outside the camp" would be outside the big conglomeration of millions of people.