OpenVZ and client /proc?

Question

OpenVZ

I want to receive container traffic counters from the root host machine. They have venet interfaces.
The official documentation recommends doing this:
vzctl exec VEID "cat /proc/net/dev"
But when the container ran out of memory or just a high load or something, it is not always possible to execute the command in this way, there is a Can't fork error, etc. d.
It would be logical to assume that it is worth digging here:
cat /vz/root/VEID/proc/net/dev
But to my surprise, there are general statistics of the server, not the container ...
Maybe someone knows what to do? Do not offer a variant with iptables from the official docks.
I dug through the entire server, I did not find anything :(