In BrE, we use the informal verbs 'pop' and 'nip' to refer to a very quick trip. For example, "I'm just nipping to the shop to get some milk". Note the addition of 'just' to emphasise the speed and ease of the trip, and the fact that we prefer the simpler word 'get' rather than 'buy' when it's obvious that you're buying something. (Similar to the way we use 'have' rather than 'eat' or 'drink'). We can also combine these words with adverbs to make useful phrasal verbs. For example, "I'm just popping out for some milk" is a very natural comment for a native BrE speaker to make. 'I'm just popping out' means that you are 'going to leave your house for a short time and return very soon', and 'for some milk' gives the reason - there's no need to specify that you're going to buy it at the shop. You don't have to state the obvious. Note also that we use these verbs in all kinds of contexts. BrE speakers nearly always excuse themselves for a 'comfort break' by saying, for example "I'm just going to nip to the loo". The choice of 'nip' and 'just' reassures the listener that your absence will be brief and won't delay anything. The verb 'pop' can be used in the same way, and has the added advantage that it is also a transitive verb meaning 'put'. For example, whenever you enter a dentist's or optometrist's room in England, they will always greet you along with the words "Just pop your things over there", indicating a chair where you can put your coat, bags and so on.

I'll be right back.

I'll be back soon