ください without て form and auxiliary verbs

Question

I read the following sentence on the shinkansen:

かけ込み電車は危ないのでおやめください

I looked up on Google but I could not find any mention of やめる being used without the て form. So why is it the case in that sentence?

Also, why is the stem of 込む used instead of the dictionary form? Why isn't there any particle indicating motion towards the train? Why is the noun at the end of the first sentence instead of the beginning? Why is かけ used?

In my mind, this is what I would have expected:

電車にかけ込むことは危ないのでやめてください。

Answer 1

おやめください

お+[連用形]+ください is an honorific language of ～～てください. So おやめください is an honorific, politer way of saying やめてください. It consists of: the honorific お + the continuative form of やめる + the imperative form of くださる.

For more on お/ご～～ください, you may want to see:
「ご覧ください」v.s.「ご覧をください」
Is "して" dropped in this phrase "ご利用{りよう}ください"?

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かけ込み電車

It should be a typo of かけ込み[乗]{じょう}[車]{しゃ}. かけ込み乗車 means かけ込んで乗車すること or 走って電車に乗ること/乗り込むこと.

かけ込み乗車 is a compound noun (複合名詞) consisting of かけ込み and 乗車. かけ込み is a noun form of かけ込む (deriving from the continuative form of かけ込む), which is a compound verb (複合動詞) made of the verbs [駆]{か}ける + 込む, literally "run/rush + go into" → "rush in".

Compound nouns with a (probably) similar structure, off the top of my head:

乗り越し運賃、詰め込み教育、投げ込み教材、居座り強盗、居眠り運転

For more on compound words (複合語), these threads might be of help:
Meaning of 盗み飲み
Dropping particles in casual speech/songs